Description
Business::GoCardless versions before 1.01 for Perl accept forged webhooks when a configured webhook secret is undef or empty.
signature_valid uses each configured secret as the HMAC key, and nothing rejects undef or an empty string, both of which Digest::SHA treats as an empty key. A secret read from an unset environment variable, or an empty entry in a list of rotated secrets, is used as is.
A remote attacker can sign a forged webhook with an empty key and have it accepted as sent by GoCardless.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Business-GoCardless | < 1.01 | 1.01 |